The objectives of the 3 year research project are to characterize meural crest migration and fusion of the facial processes during the early and late phases of facial development, to develop an experimental animal model for the study of cleft palate and associated orofacial malformations, and to study the postnatal growth patterns of the face in offspring with experimentally induced malformations. Neural crest migration and fusion of the facial processess will be studied by stereoscan electron microscopy in order to analyze their respective roles in abnormal development of the face and cranium. Induction of orofacial malformations, with emphasis on cleft palate, will be done with drugs shown to be teratogenic in other laboratory animals and for which preliminary data are available from our laboratory. The corticosteroid, triamcinolone, the anticonvulsant, diphenylhydantoin, the lathyrogens, aminoacetonitrile and beta- aminoproprionitrile, and hypervitaminosis A are among the drugs proposed for use. Cleft palate and associated orofacial defects have been induced in rhesus monkeys, bonnet monkeys, and baboons with all the agents except diphenylhydantoin. Postnatal growth patterns of offspring with craniofacial malformations will be followed radiologically.